Ping pong ball hail in Lubbock CWA

Back in the Lubbock CWA, we were monitoring a storm for a long period of time southeast of Lubbock.  The ProbSevere values fluctuated over time, generally in the 50-70% range.  Suddenly at 2338 UTC, the ProbSevere value jumped from 65% at 2336 UTC to 88% in response to an increase of the MRMS MESH from 0.76" to 1.15".  Additionally, this storm had moderate vertical growth rates, strong glaciation rates, and was an environment of very high effective bulk shear (~53 knots).  Figure 1 shows the progression of ProbSevere values from 2336 UTC to 2345 UTC when ping pong ball sized hail was reported by an NWS employee, or about 8 minutes of lead-time from the 65 to 88% jump.

Figure 1. 0.5 degree KLBB reflectivity and NOAA/CIMSS ProbSevere contours valid 2336 - 2344 UTC 20 April 2016.

-Sieglaff